Certain ophthalmic conditions, such as uveitis, wet and dry age-related macular degeneration (AMD), diabetic macular edema (DME), diabetic retinopathy (DR) and keratomycosis, require long-term treatment. While drug treatments can be given systemically (e.g., orally), such treatment exposes the entire body to the drug, and is not able to focus the treatment on the area in greatest need of treatment. An ophthalmic depot formulation should be able to concentrate treatment on the area in need of treatment, while reducing systemic exposure of patients' bodies to the medication, and reducing frequency of administration.
However, ophthalmic depot formulations are more challenging to develop than other implants and depot formulations. An ophthalmic depot must minimize, or preferably completely avoid, affecting vision, but the eye has limited space, and may be sensitive to pressure and/or distortion. Thus an ophthalmic depot formulation—whether, e.g., intra-humorous or subconjunctival—should be limited in physical size, i.e., volume. However, the depot formulation should at the same time contain enough active pharmaceutical ingredient (API) to avoid the need for frequent re-application (since application methods are typically invasive and inconvenient, e.g., by injection in a hospital or clinical setting).
With regard to intra-humorous (e.g., intra-vitreous) depots, because these are placed into fluid environments, it is also important for the depot to remain cohesive. A depot that is not cohesive can break up into many separate globules. These globules have a greater collective surface area than a cohesive depot, which can affect the rate of API release. A large number of globules also has the potential to adversely impact vision.
Implanted or injected formulations, such as ophthalmic (e.g., intra-vitreous) depots, are highly invasive, inconvenient, and may require administration by a healthcare professional. Therefore, it is usually considered advantageous for depot formulations to exhibit controlled or extended release after the pharmaceutical composition is administered to the patient, and which preferably exhibits continued drug efficacy over a long period.
There remains a long-felt need for improved depot formulations, including ophthalmic depot formulations and methods for treating ophthalmic conditions. For instance, there remains a long-felt need for sirolimus depot formulations and methods of use thereof for treating ophthalmic conditions. There remains a long-felt need for a depot formulation, including an ophthalmic depot formulation, capable of providing sustained release of an active ingredient. There remains a need for depot formulations, preferably ophthalmic depot formulations, which attain sustained release via a composition consisting essentially of an active pharmaceutical ingredient, a high viscosity liquid carrier material (HVLCM), a hydrophobic solvent; and a hydrophilic solvent, which composition preferably does not comprise other excipients materially affecting the rate or extent of the sustained release.